1973 9.5hp Johnson that really smokes too much...

dfrants

Chief Petty Officer
Joined
Jul 26, 2008
Messages
405
I got a 1973 9.5hp Johnson "lowboy" motor. I finally got it to start and run pretty good but she really smokes. Ive replaced the coils, points, condensers, plugs, needle, seat, float and the o-ring around the slow speed needle. It seems like its running too rich, but if I lean up the slow idle adjustment it just coughs and dies out. She has good spark in both cylinders. I have 5 of these kind of motors and got 4 of them running very good...this one is giving me fits. Any ideas what could a motor to smoke too much?
 

interalian

Commander
Joined
Jul 23, 2009
Messages
2,105
Do a 'cylinder drop' test. Make sure it's running on both. Excess smoke is rich, or one cylinder not burning the mix, or an excessively rich oil ratio. But running in a barrel vs on a boat can mislead.
 
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